Just a few months of maturity can give older students an edge that may persist for years.......if you take two children who are intellectually equivalent but were born at opposite ends of the cut-off date for school entry, the older child could have scores that make her appear gifted while the younger child appears to be merely average. And instead of disappearing over time, these differences seem to persist. In British Columbia, Dhuey found that younger students are almost 10 per cent less likely to be in the highest academic stream in high school.
This phenomenon and Dhuey’s research was cited in Outliers, the best-selling book by Malcolm Gladwell and has led to an increase in “redshirting,” parents holding their children back from kindergarten so they can start school when they are older and more mature. The practice of redshirting has more than tripled in the U.S. since the 1970s. While redshirting does not appear to be as prevalent in Canadian schools, the effects of relative age in our classrooms are very real. A more recent Canadian study by Justin Smith of Wilfrid Laurier University found that younger students performed significantly worse in reading and math in both Grade 4 and Grade 10.